Tuning the Length of Cooperative Supramolecular Polymers under Thermodynamic Control

In the field of supramolecular (co)polymerizations, the ability to predict and control the composition and length of the supramolecular (co)polymers is a topic of great interest. In this work, we elucidate the mechanism that controls the polymer length in a two-component cooperative supramolecular polymerization and unveil the role of the second component in the system. We focus on the supramolecular copolymerization between two derivatives of benzene-1,3,5-tricarboxamide (BTA) monomers; a-BTA and Nle-BTA. As a single component, a-BTA cooperatively polymerizes into long supramolecular polymers, whereas Nle-BTA only forms dimers. By mixing aBTA and Nle-BTA in different ratios, two-component systems are obtained, which are analyzed in-depth by combining spectroscopy and light-scattering techniques with theoretical modeling. The results show that the length of the supramolecular polymers formed by a-BTA is controlled by competitive sequestration of a-BTA monomers by Nle-BTA. While the obvious alternative Nle...